I usually point out in my human sexuality class, that although animals do engage in homosexual behavior, it is not particularly informative to look to animals for information about what is "normal". Many (most?) human behaviors are unparralled among animals, but does that make them abnormal? That is, we fly airplanes, drive cars, sit on chairs, wear socks and engage in 1000s of other behaviors which animals don't. So should we consider such behaviors abnormal?
Also animals are so varied in their behavior that we can pick almost any sexual behavior and find an animal which supports this particular behavior as "normal". Here is a list that I share with my human sexuality students (from Nevid and Rathus, Feb 1992 reported in a instructors manual)
1. Though wolves and beavers generally keep a mate for life, most mammals copulate with multiple partners thoughout their sexual careers. Is nature serving as a model for promiscuity?
2. Rhinoceri mate continiously for one and a half hours. The male ejaculates numerious times with his two-feet-long penis. For chimpanzees, it is all over in less than 30 seconds. Which scenario provides the "natural" model for humans?
3. The female Praying Mantis decapitates the male and eats his head during copulation as a form of fodder. (His nether parts continue to thrust). Is nature saying that males should literally lose their heads in love? Should sex literally consume us? Is the Mantis' nature a wry comments on the value of male's brains?
4. The male porcupine will thoroughly douse the female with uring before mating. (No comment).
5. Cobras of both sexes strike at each other for an hour or more before mating. Is nature advocating S & M?
Marie Helweg-Larsen, Ph.D. [From TIPS list of March '97]
http://blue.butler.edu/~bwoodruf/allian ... nimals.htm